1. Field of the Invention
The invention is related to the field of apparatus for treating floors of stone or stone like material.
2. Description of the Related Art
Such apparatus are well known per se, and are applied for several kinds of treatments. For instance, by means of an apparatus equipped with suitable grinding discs, the process of grinding of floors for the purpose of smoothening new or worn out floors can be carried out. Also, such apparatuses can be used for daily maintenance of heavily used stone floors, such as the floors in public areas, in retail buildings and the like.
The heads of the apparatus may thus be provided with several types of grinding discs or maintenance pads and the like. The heads are usually driven by means of an electric motor which is supported on the frame of the apparatus. At the same time, the housing of the apparatus is slowly driven in rotation as well so as to stabilize the behavior of the apparatus and to simplify handling thereof by the operator. The housing rotation is usually obtained from the same electric motor which drives the heads.
Several proposals have been made for enabling the single electric motor to drive both the heads as well as the housing at the required rotational speeds. As mentioned, the housing is rotated at a lower speed than the heads. This entails different drives for the heads on the one hand, and the housing on the other hand. Examples of such apparatuses are given in U.S. Pat. No. 6,783,447, U.S. Pat. No. 7,241,210, EP-A-1,915,232, WO-A-94/08752 and WO-A-02/062524.